The present invention relates to a transducer of the type in which the magnitude of an input signal produces a corresponding change in the output signal of a relay. In its more detailed aspects, the invention relates to an electrical-pneumatic transducer wherein the magnitude of an electrical signal produces a corresponding change in the pressure at the outlet of a pneumatic relay. Customarily, the signal magnitude is responsive to changes in a variable condition and the output of the relay is used to control the magnitude of that condition. The relay is of the type in which the pressure of the air at the outlet is varied in accordance with the back pressure at the bleed nozzle and that pressure is determined by the force on a member movable relative to the nozzle and hence by the position of the member. An example of such a relay is shown in Taylor U.S. Pat. No. 3,244,190. The force on the movable member is correlated with the magnitude of the electrical signal through the medium of a signal-to-force transducer such as a solenoid.